What the Supreme Court's Geofence Warrant Case Means for Your Privacy

The Supreme Court heard arguments this morning in Chatrie v. United States, a case that will decide whether police can use "geofence warrants"—a surveillance tool that has become routine in criminal investigations over the past decade. Chief Justice Roberts presided, and based on questions from the bench, several justices seemed open to supporting this police practice.

The case involves Okello Chatrie, convicted of armed robbery after police used a geofence warrant to identify his cellphone as one of several devices near a Virginia bank during a 2019 heist. Once they knew his location was in the area, they obtained a traditional search warrant for his home and found evidence that led to his conviction.

How Geofence Warrants Actually Work

A geofence warrant is essentially a digital dragnet. Police ask a company—usually Google—to hand over location data for every cellphone in a specific area during a specific time window. The process typically unfolds in three steps: law enforcement first gets anonymized data showing all devices in the zone, then narrows down to devices of interest, and finally requests subscriber information to identify individuals by name.

This is quite different from older cell tower methods, which required police to start with a known suspect and track their movements. Geofence warrants flip the approach: collect everyone's location data first, figure out who was actually there later.

The practice has exploded since around 2016. Court filings show Google fielded more than 11,000 geofence requests from U.S. law enforcement in just the first half of 2020 alone.

The Legal Question at Stake

The Fourth Circuit Court of Appeals upheld the warrant, ruling that Chatrie had no legitimate privacy expectation because he voluntarily shared his location history with Google. His lawyers, led by Adam Unikowsky, argued that geofence warrants violate the Fourth Amendment requirement that warrants be specific about what police are searching for—but the justices did not appear sympathetic to that argument.

This case landed at the Supreme Court because lower courts have split. A federal appeals court in New Orleans took the opposite view, calling geofence warrants unconstitutional. The justices needed to settle the question.

Why This Matters Beyond One Case

The broader context here is that the Supreme Court has grappled with digital surveillance before. In 2018, in a case called Carpenter v. United States, the Court ruled 5-4 that tracking someone's cellphone movements for months without a warrant violated the Fourth Amendment. But Carpenter left a gap: it did not clearly say what happens with shorter bursts of location data, or whether it matters that you voluntarily gave your location history to a company.

Geofence warrants test those gaps. They typically cover just minutes or hours around a crime, not months of surveillance. And they rely on the fact that millions of people have turned on Location History in their Google accounts without fully understanding that police can later access that data through a warrant.

The Court's leanings matter because this is just the start. Law enforcement is increasingly turning to digital tools—facial recognition, license plate readers, social media analytics. The constitutional rules the Court sets in Chatrie will shape how courts evaluate all these technologies down the line.

Who Wants What in This Case

Civil liberties organizations lined up against the geofence warrant practice. The ACLU, Electronic Frontier Foundation, and Georgetown Law's Center on Privacy & Technology all filed briefs supporting Chatrie, as did other groups including the Brennan Center and Center for Democracy and Technology.

On the other side, local government associations filed briefs backing law enforcement, saying geofence warrants are essential tools for solving crimes. Google has already made some internal changes to limit how much data it hands over, but the company's official position in this case remains neutral.

What Comes Next

If the Court rules in favor of geofence warrants, it will likely open the door to broader police use of location data and possibly other bulk collection methods from tech platforms. For Google and other companies, it could reshape their obligations around data cooperation with law enforcement.

The decision is expected by June, when the Court's current term ends. Whatever the outcome, this case is likely to influence how courts think about privacy in an era when nearly everyone carries a device that continuously broadcasts their location.